From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net 2/2] macvtap: signal truncated packets Date: Tue, 10 Dec 2013 13:41:53 +0800 Message-ID: <52A6A9A1.8080703@redhat.com> References: <1386584717-5776-1-git-send-email-jasowang@redhat.com> <1386584717-5776-2-git-send-email-jasowang@redhat.com> <20131209110251.GE15055@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Vlad Yasevich , Zhi Yong Wu To: "Michael S. Tsirkin" Return-path: In-Reply-To: <20131209110251.GE15055@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 12/09/2013 07:02 PM, Michael S. Tsirkin wrote: > On Mon, Dec 09, 2013 at 06:25:17PM +0800, Jason Wang wrote: >> macvtap_put_user() never return a value grater than iov length, this in fact >> bypasses the truncated checking in macvtap_recvmsg(). Fix this by always >> returning the size of packet plus the possible vlan header to let the truncated >> checking work. >> >> Cc: Vlad Yasevich >> Cc: Zhi Yong Wu >> Signed-off-by: Jason Wang > Same comments as for tun really, but here it's also > kind of ugly to call a variable copied if we don't copy. > > Also, maybe we should name the variable "copied" for tun, > this would make the code more similar. Agree, but better with a separate patch for net-next. >> --- >> The patch is needed for stable. >> --- >> drivers/net/macvtap.c | 27 ++++++++++++++------------- >> 1 file changed, 14 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c >> index 957cc5c..7544a0c 100644 >> --- a/drivers/net/macvtap.c >> +++ b/drivers/net/macvtap.c >> @@ -767,10 +767,14 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, >> const struct sk_buff *skb, >> const struct iovec *iv, int len) >> { >> - int ret; >> + int ret, off; >> int vnet_hdr_len = 0; >> int vlan_offset = 0; >> int copied; >> + struct { >> + __be16 h_vlan_proto; >> + __be16 h_vlan_TCI; >> + } veth; >> >> if (q->flags & IFF_VNET_HDR) { >> struct virtio_net_hdr vnet_hdr; >> @@ -785,16 +789,13 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, >> if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr))) >> return -EFAULT; >> } >> - copied = vnet_hdr_len; >> + off = copied = vnet_hdr_len; >> >> if (!vlan_tx_tag_present(skb)) >> len = min_t(int, skb->len, len); >> else { >> int copy; >> - struct { >> - __be16 h_vlan_proto; >> - __be16 h_vlan_TCI; >> - } veth; >> + >> veth.h_vlan_proto = skb->vlan_proto; >> veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); >> >> @@ -802,22 +803,22 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, >> len = min_t(int, skb->len + VLAN_HLEN, len); >> >> copy = min_t(int, vlan_offset, len); >> - ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); >> + ret = skb_copy_datagram_const_iovec(skb, 0, iv, off, copy); >> len -= copy; >> - copied += copy; >> + off += copy; >> if (ret || !len) >> goto done; >> >> copy = min_t(int, sizeof(veth), len); >> - ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); >> + ret = memcpy_toiovecend(iv, (void *)&veth, off, copy); >> len -= copy; >> - copied += copy; >> + off += copy; >> if (ret || !len) >> goto done; >> } >> >> - ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); >> - copied += len; >> + ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, off, len); >> + copied += skb->len + (vlan_offset ? sizeof(veth) : 0); >> >> done: >> return ret ? ret : copied; >> @@ -875,7 +876,7 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv, >> } >> >> ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK); >> - ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */ >> + ret = min_t(ssize_t, ret, len); >> if (ret > 0) >> iocb->ki_pos = ret; >> out: > > >> -- >> 1.8.3.2 > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html